1. Field of the Invention
The present invention relates to an antenna diversity apparatus and an antenna diversity method, and more particularly, to an antenna diversity apparatus and an antenna diversity method capable of switching antennas fast.
2. Description of the Prior Art
In order to determine which antenna has a better signal quality, the conventional method (such as Taiwan Patent No. 256,205) using a certain antenna to receive packet information (such as receiving signal strength and receiving signal quality, etc. . . . ) for a specific time period, and then determine whether to switch antenna according to the statistic result. Since the conventional method constantly uses the certain antenna to receive packets, if the conventional method selects an antenna having worse receiving signal quality, then there will be burst error during the specific time period, and result in lower packet transmitting data rate for the transmitting terminal at the opposite side.
Please refer to FIG. 1 and FIG. 2. FIG. 1 shows a simplified block diagram of an antenna diversity apparatus 100 of Taiwan Patent No. 256,205. FIG. 2 is a flowchart showing an antenna diversity method of Taiwan Patent No. 256,205. The antenna diversity method uses an initial antenna to receive transmitted signals for a specific time period, and record a statistic result of the receiving signal quality of the initial antenna. Next, the antenna diversity method switch to another antenna from the initial antenna, and record another statistic result of the another antenna. Afterwards, the antenna diversity method compares the statistic results of these two antennas, so as to decide which antenna has a better receiving signal quality, and then the antenna diversity method controls the switching unit 130 to switch to the antenna having the better receiving signal quality. As to this antenna diversity method, since there are a plurality of packets during the specific time period of switching antennas, when the antenna diversity method controls the switching unit 130 to switch to the antenna having the worse receiving signal quality, there will be burst error to reduce transmitting data rate. In addition, when variation of the data transmission channels occurs, it will take a longer time to re-find an antenna and switch to the optimal antenna.